The single most astonishing fact about foreign exchange is not the high volume of transactions, as incredible as that growth has been. Nor is it the volatility of currency rates, as wild as the markets are these days.

Instead, it’s the extent to which the market remains dollar-centric.

Consider this: When a South Korean wine wholesaler wants to import Chilean cabernet, the Korean importer buys U.S. dollars, not pesos, with which to pay the Chilean exporter. Indeed, the dollar is virtually the exclusive vehicle for foreign-exchange transactions between Chile and Korea, despite the fact that less than 20% of the merchandise trade of both countries is with the U.S.